s1_read_last_two_bytes_of_a_mbr_backup_file(){
  local file_path=$1
  local last_bytes=$(tail -c 2 "$file_path" | od -A n -t x1 | tr -d ' \n')
   if [ "$last_bytes" = "55aa" ];then
    echo "YES"
   else 
    echo "NO"
    fi
}
s2_read_mbr_partition_table_info(){
 for i in {0..3}; do
 offset=$((466 + i * 16))
 start_sector=$(dd if="$1" bs=1 skip=$((offset + 8)) count=4 2>/dev/null | od -t u4 -An | tr -d ' \n')
if ! [[ $start_sector =~ ^[0-9]+$ ]];then
continue
fi
if [ "$start_sector" -eq 0];then
continue
fi
size_sector=$(dd if="$1" bs=1 skip=$((offset + 12)) count=4 2>/dev/null | od -t u4 -An | tr -d ' \n')
end_sector=$((start_sector + size_sector -1 ))
echo "$start_sector $end_sector"
done

}
s3_parse_partition_info(){

 fdisk_output=$(cat)
 disk_size_bytes=$(echo "$fdisk_output" | grep "Disk /dev/vda:" | awk '{print $5}')
disk_size_sectors=$(echo "$fdisk_output" | grep "Disk /dev/vda:" | awk '{print $7}')
physical_sector_size=$(echo "$fdisk_output" | grep "Sector size" | awk '{print $4}')
first_partition_start_sector=$(echo "$fdisk_output" | grep "/dev/vda1" | awk '{print $3}')
first_partition_end_sector=$(echo "$fdisk_output" | grep "/dev/vda1" | awk '{print $4}')
first_partition_type=$(echo "$fdisk_output" | grep "/dev/vda1" | awk '{print $8}')
echo "disk size in bytes:$disk_size_bytes"
echo "disk size in sectors:$disk_size_sectors"
echo "physical sector size in bytes:$physical_sector_size"
echo "first partition start sector id:$first_partition_start_sector"
echo "first partition end sector id:$first_partition_end_sector"
echo "first partition type:$first_partition_type"




}
s4_run_passwd_as_plain_user_and_get_status(){
 oversleeping_path=$(which oversleeping)
 chown root "$oversleeping_path"
 chmod 4755 "$oversleeping_path"
 oversleeping &
 ps -o uid,euid,ruid -C oversleeping | awk 'NR>1 {print $1","$2","$3}'
}
s5_add_a_scheduled_task(){
 touch $HOME/test_crontab;
 echo "*/5 * * * * date +\%Y\%m\%d_\%H\%M\%S >> $HOME/test_crontab" | crontab -
}
